Toluene Caprolactam Oxidation Section Process Energy Optimization Analysis

Caprolactam is an important chemical raw material it is mainly used in the production of Nylon-6staple fiber. With the polyamide engineering plastics and other industries developing, the social demand of caprolactam is increasing every year, our country is still in the state of short supply. In order to adapt the developing need, many domestic caprolactam producers expand their productions in succession. Nowadays, the output of Sinopec Shijiazhuang refining branch is16wt/a, which developing from the initial5wt/a after revamping two times.Caprolactam device is consisted by many sets of equipment, the production will consume much energy, and it can recycle the heat in different place in the same time, the energy system is every complex. Owing to many times revamping, the running state of the device is far away from the first design working condition. Because the reform based on the original device, and it mainly focused on revamping, the energy system is not being optimized at the same time. This could cause the unreasonable using of energy, and there is much energy-saving space in these enterprises.This paper is mainly does the energy utilization analysis and optimization of utility system and the oxidation process of caprolactam production which used in Sinopec Shijiazhuang refining branch. It starts with response unit and the overall process and explores an effective way to improve comprehensive utilization ratio of energy system. It finally accomplishes energy optimization after many times field researching, data checking, theory analyzing, analog computing and docking solution. This paper uses ASPEN PLUS to simulate and combines with actual operating parameters to adjust data, bases on the pinch technology to optimizing the heat exchanger network and analyzing the energy using of process system, and to analyzing&optimizing recirculating cooling water system according to the mathematical programming method. The analog computing of oxidation unit shows the current heat exchanger network heating utilities total9108.7kW of cooling public works Total35534. lkW. The energy-saving potential of this device is3553.7K.W which takes the39%parts of nowadays heating utilities, and10%parts of cooling utilities. It can save222.6kW MPS(0.5t) and702kw HPS(1.4t) according to the improvement programs. The analog computing of utilities shows the total water flowing rate of cooling tower is710.9t/h after optimizing and it can save water flowing rate of cooling tower is201.2t/h, it takes the22.1%parts of the total current circulating cooling water. The steam system can recycle155640kwh power every year. Because the running condition of caprolactam device is strictly, and it is restricted by field condition, some programs may be well in theory, but it has some difficulties during the paretical application. On the whole, our work shows clearly the possibility of the energy of caprolactam production is more efficiency and provides direction for future endeavors...